We report chemically exfoliated MoS2 nanosheets with a very high concentration of metallic 1T phase using a solvent free intercalation method. After removing the excess of negative charges from the surface of the nanosheets, highly conducting 1T phase MoS2 nanosheets exhibit excellent catalytic activity toward the evolution of hydrogen with a notably low Tafel slope of 40 mV/dec. By partially oxidizing MoS2, we found that the activity of 2H MoS2 is significantly reduced after oxidation, consistent with edge oxidation. On the other hand, 1T MoS2 remains unaffected after oxidation, suggesting that edges of the nanosheets are not the main active sites. The importance of electrical conductivity of the two phases on the hydrogen evolution reaction activity has been further confirmed by using carbon nanotubes to increase the conductivity of 2H MoS2.

Conducting MoS2 Nanosheets as Catalysts for Hydrogen Evolution Reaction

Remarkable hydrogen evolution reaction (HER) or superior oxygen evolution reaction (OER) catalyst has been applied in water splitting, however, utilizing a bifunctional catalyst for simultaneously generating H2 and O2 is still a challenging issue, which is crucial for improving the overall efficiency of water electrolysis Herein, inspired by the superiority of carbon conductivity, the propitious H atom binding energy of metallic cobalt, and better OER activity of cobalt oxide, we synthesized cobalt–cobalt oxide/N-doped carbon hybrids (CoOx@CN) composed of Co0, CoO, Co3O4 applied to HER and OER by simple one-pot thermal treatment method CoOx@CN exhibited a small onset potential of 85 mV, low charge-transfer resistance (41 Ω), and considerable stability for HER Electrocatalytic experiments further indicated the better performance of CoOx@CN for HER can be attributed to the high conductivity of carbon, the synergistic effect of metallic cobalt and cobalt oxide, the stability of carbon-encapsulated Co nano

In situ cobalt-cobalt oxide/N-doped carbon hybrids as superior bifunctional electrocatalysts for hydrogen and oxygen evolution.

There is ongoing research into new electrocatalysts for hydrogen production from water splitting. Here, the authors report the electrocatalytic performance of nickel/nickel oxide heterostructures on carbon nanotubes, and are able to assemble a water electrolyzer operated by a single-cell 1.5 V battery.

http://www.overunityresearch.com/index.php?action=dlattach;topic=2578.0;attach=14737

Nanoscale nickel oxide/nickel heterostructures for active hydrogen evolution electrocatalysis

Recovery and recycling of lithium: A review

Tremendous efforts are being made to develop electrode materials, electrolytes, and separators for energy storage devices to meet the needs of emerging technologies such as electric vehicles, decarbonized electricity, and electrochemical energy storage. However, the sustainability concerns of lithium-ion batteries (LIBs) and next-generation rechargeable batteries have received little attention. Recycling plays an important role in the overall sustainability of future batteries and is affected by battery attributes including environmental hazards and the value of their constituent resources. Therefore, recycling should be considered when developing battery systems. Herein, we provide a systematic overview of rechargeable battery sustainability. With a particular focus on electric vehicles, we analyze the market competitiveness of batteries in terms of economy, environment, and policy. Considering the large volumes of batteries soon to be retired, we comprehensively evaluate battery utilization and recycling from the perspectives of economic feasibility, environmental impact, technology, and safety. Battery sustainability is discussed with respect to life-cycle assessment and analyzed from the perspectives of strategic resources and economic demand. Finally, we propose a 4H strategy for battery recycling with the aims of high efficiency, high economic return, high environmental benefit, and high safety. New challenges and future prospects for battery sustainability are also highlighted.

Sustainable Recycling Technology for Li-Ion Batteries and Beyond: Challenges and Future Prospects.

Nickel–cobalt electrodeposited alloys for hydrogen evolution in alkaline media

Nickel and cobalt recycling from lithium-ion batteries by electrochemical processes

Electrolytic nickel recovery from lithium-ion batteries

The electrodeposition conditions for Zn–Ni alloys from sulfate–acetate electrolytes have been studied with the view of preparing protective coatings. The influence of electrolyte composition (different [Ni(II)]/[Zn(II)] ratios, pH, buffer), cathode current density, cathode potential and hydrodynamic conditions on the composition of coatings, cathode current efficiency and corrosion resistance were determined. For all of the conditions examined, strong inhibition of nickel reduction with simultaneous increase in the rate of zinc discharge characteristic of an anomalous system, have been observed. The Zn(II) discharge becomes diffusion-controlled at more negative cathode potentials, whereas the partial nickel current densities are independent of electrode rotation speed. Consequently, nickel content and current efficiency are reduced with decreasing thickness of the diffusive layer. An increase in pH above 3.3 causes a significant catalysis of Zn–Ni deposition with a simultaneous decrease of the nickel in coatings. This effect may be related to the formation and increasing concentration of Zn(II) and Ni(II) acetate complexes in this condition. The Zn–Ni coatings obtained (5–18% Ni) characterise improved corrosion resistance in comparison to Zn layers deposited under the same conditions.

Electrodeposition of Zn–Ni protective coatings from sulfate–acetate baths

Nickel–cobalt alloys having settled composition can be produced by electrolysis after optimising process operative conditions. In this work nickel–cobalt coatings on 1050 Al net, obtained by electrodeposition under galvanostatic conditions, were investigated. Ni–Co coatings were electrowon, from an acidic sulphate bath containing 40 g/L Ni and Co in the range 0.1–16 g/L, at 60 °C temperature and 300 A/m2 average current density. The experimental results highlight a linear correlation between bath and deposit Co/Ni ratio, with slope change for Co concentration in the electrolyte higher than 3 g/L. Morphology, structure and electrochemical properties are strictly correlated among themselves and with the composition of the coating.

Carla Lupi

Papers

Nickel–cobalt electrodeposited alloys for hydrogen evolution in alkaline media

Nickel and cobalt recycling from lithium-ion batteries by electrochemical processes

Electrolytic nickel recovery from lithium-ion batteries

Electrodeposition of Zn–Ni protective coatings from sulfate–acetate baths

Composition, morphology, structural aspects and electrochemical properties of Ni–Co alloy coatings